Method of sealing packages



Patented Nov. 13, 1934 v UNITED. STATES PATENT OFFICE- No Drawing. Application October 28, 1930, Serial No. 491,737

6 Claims. (Cl. 21662) My invention relates to methods of sealing packages, and particularly to a novel method of sealing packages which have been wrapped with cellulose hydrate material, which has a soluble moisture-proof constituent.

In the art there has been'a constantly growing demand for packages wrapped with moistureproof cellulose hydrate or other similar material. Food products, tobacco articles, candies, and

10 many other articles of merchandise have a neater, and more sanitary appearance, and preserve their natural moisture and flavor if they are wrapped in cellulose hydrate material or one of its equivalents. Further, articles which tend to become moistened by exposure to the atmosphere, are preserved in better condition if they are wrapped with moisture-proof material.

To secure proper adhesion of moisture-proof material, either to a paper blank or tape, has required an extended drying period because the moisture-proof layer of the cellulose hydrate material does not permit air to pass through its interstices and thus produce a drying effect.

It is the object of my invention to treat the surfaces of the materials which it is desired to adhere together so that practically instant adhesion will result. In the use of water soluble, adhesive coatedtape for binding and wrapping packages, when the adhesive coated surface is moistened, practically instant adhesion will result. If, however, wet adhesive is applied to two surfaces which it is desired to secure together, a long drying period is necessary. My process has a similar effect.

My invention consists in providing a method for adhesively securing together a moistureproof sheet and a paper or other surface, in which the time required for securing effective adhesion is greatly minimized over that formerly required. A specific object is to treat the surfaces of a moisture-proof sheet with a dissolvent which penetrates the moisture-proof surface, and which will soften a'coating of a spirit gum which has been previously applied to a paper blank to which the moisture-proof material is to be secured, or

with which the moisture-proof surface is desired to be secured to another moisture-proof surface. Another specific object is to apply the cellulose hydrate dissolvent first to the spirit gum treated surface and subsequently to bring the moistened surface into contact with the moisture-proof surface.

Packages of shirts, for example, are formed with a sheet of cardboard, with moisture-proof .55 cellulose hydrate material adhesively secured about the-cardboard sheet forming a tubular container, and with the ends of the material lapped over the back of the sheet and secured toit. For wrapping bread and other food products,

I often a container is employed which is complete- 0 1y enclosed in a moisture-proof sheet and with paper stickers or tape employed to bind together the end folds of the material.

The sides or desired areas of stickers, paper, Wood, metal blanks, or tape, may be treated with any suitable spirit gum or adhesive. I find that one type of gum which responds readily to the softening of a material which will penetrate the waterproof coating of cellulose hydrate sheet material may be made on the following formula:

-{ Butyl acetate Volatile constituents Ethyl acetate Toluol acetate Gum resins soluble in benzol and melting just below boiling point of water 21. 48 Nitro-cellulose a- 15. 51 Insoluble 56 For softening the moisture-proof surface of the cellulose hydrate sheet I employ one or more of the volatile ingredients of the spirit gum, or I may employ amyl acetate. In fact any compound which has the property of both softening the surface of the moisture-proof sheet which is employed as a wrapper and which will also soften the spirit gum, previously coated on the surface to which the wrapper is to be applied, may be employed with satisfactory results. While I have disclosed one specific formula for a spirit gum, it will be readily understood that other formulas of non-water soluble adhesive may be employed. Even water soluble adhesives may be employed if the solvent for the moisture-proof sheet has the elfect of making the adhesive coating tacky so that quick adhesion will result.

Cellulose hydrate in sheet form is on the market in two commercial grades, one called moistureproof, and the other slightly penetrated by moisture. While my process is applicable to either grade, it is more necessary with the first noted quality.

My process may also be employed by'applying the solvent to the spirit gum coated surface, and this is just as satisfactory for certain kinds of Work and no longer interval is required for the solvent to penetrate the moisture-proof sheet. In

Solid constituents 37. 55

fact, in a number of cases, treating the gummed surface is preferable.

If it is desired to quicken the time of adhesion of a wax or paraflin coated wrapper to a surface coated with an adhesive having benzol as its dissolvent, some solvent such as benzol, which will soften the surface of the sheet and at the same time moisten the adhesive coating, may be employed.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:-

1. A. method of securing quick adhesion between a'sheet which has a water-repellent surface and the surface of a gum which has been applied to a water absorptive article by means of .together for penetration of both surfaces by the solvent and for immediate drying and fixed connection due to the volatility of the solvent after its penetration of the two surfaces and bonding of the materials thereof.

5. A method as set forth in claim 1, in which the 1 solvent for the gum, when it was applied to the article, comprises a mixture of butyl, ethyl and toluol acetates, and is in major proportion in the total solvent and gum composition.

6. A method as set forth in claim 1, in which the sheet material is a cellulosic derivative, and in which the solvent for the gum, when it is applied to the article, is combined with nitro-ccllu- .lose n addition to being combined with the gum.

SAMUEL BERQGS'I'EIN. 

